Video distribution at home

25Jun10

I touched upon some time ago when I bought my new DVR. The question is how are we going to achieve distribution of video around the home when analogue TV goes away?

The good old way

I spent part of fathers day setting up distribution in my in law’s new place. They live in a place where Freeview doesn’t reach yet, so their needs were simple – redistribution of the analogue TV signal (BBC1/2, ITV and C4) along with the output of their Sky+ box. This couldn’t be easier, as the Sky+ has an analogue in for the Antenna and two outputs – one for the nearby TV and another specifically for the purpose of redistribution. All I needed to do was connect the redistribution output to an amplifier (luckily their was already a coax cable running back up to the loft) and then drop cables from the amp to the other TVs they wanted. Had I researched this properly before coming up with the bill of materials my father in law could have even bought a special type of amplifier with ‘bypass’ functionality that would facilitate a Sky ‘magic eye’ – a device that beams remote control commands back to the Sky box via redistribution connection, which is great if you want to be able to change channels in another room.

But analogue is going away

In the next couple of years the analogue TV signal is being switched off across the UK. This means that there’s no immediate point in TV makers incorporating the electronics to receive analogue signals, and as I observed with my DVR many equipment makers are assuming that you’ll connect via a better quality connection than UHF RF (e.g. HDMI, Component, Scart etc.). So both ends of the analogue connection are disappearing – so what are the alternatives?

Wireless Senders

These are boxes (normally shipped as a pair – a sender and a receiver) that retransmit a composite video and audio signal over unlicensed spectrum (2.4GHz). In my experience they’re awful, which is pretty predictable – composite video is the lowest common denominator to video interconnect (and only one step of degradation better than UHF), and the 2.4GHz band is full of other stuff that you probably already have – WiFi, DECT phones, MicroWave ovens (though you’d hope they’re not leaking).

Wired Senders

I’ve seen devices that can take a VGA signal from one room to another over Cat 5 cabling. These seem to work OK, but the one’s I’ve come across seem to be aimed at the business market rather than domestic use (with pricing set accordingly). I also suspect that they’re not properly network friendly – expecting a dedicated set of twisted pairs.

Media servers/players

I’m a big fan of media servers (and associated players like the Kiss DP-500 it’s HD sibling the DP-600, which I’ve had for some time now [1]). These are fine for watching content libraries in different rooms, but there are some issues:

  • Building a legal content library is tough – video has been slow to follow music into using formats with DRM and other encumbrances.
  • It’s not a multi room solution – even with multiple players there’s no way to achieve audio/video sync as you walk from room to room.
  • It can only deal with stale content rather than live events.

Slingbox

Slingbox make devices that can digitally encode a video signal and stream it to a receiver. Sadly these are crippled so that only one receiver can connect at a time, and it also seems that the dedicated receiver (the ‘SlingCatcher’) isn’t made any more. I also had concerns about picture quality on these, which were conceived to stream SD video over the Internet (though an HD version came along later) rather than high quality video around a house.

Pay up

You can of course just pay content distributors (like Sky) for multiple boxes for multiple rooms. This works fine for live events, and covers watching different recordings in different rooms, but doesn’t deal elegantly with watching the same recording in multiple rooms – time for some home network friendly features on those boxes perhaps (once the Holywood DRM Stasi figue out a way to lock things down to their satisfaction).

and that’s about it

it seems that multi room TV is coming to an end, but I have some ideas…

  • HDMI redistribution – seems like a really good plan, at least that is until HDCP enters the frame. Sadly the whole point of HDCP is to limit HDMI to a conversation between one playback device and one viewing device. I keep wondering what happens when TVs with HDMI/HDCP get beyond their useful lives and hackers start doing their thing? If it ever happens then HDMI redistribution would be tricky cabling wise unless it can use a home network in the middle (which brings its own challenges with bandwidth).
  • Live re(encoding) – it’s been possible to do real time MPEG4 (or similar) encoding of SD video for some time on a single x86 core. With a bit of dedicated GPU assistance I’ve no doubt that HD would be feasible these days. All that would be needed then is players capable of doing streams rather than files (hardly a problem). This is basically Slingbox for the home (with maybe extensions over the Internet for remote viewing).
  • Get at the digital stream at its source. PC based DVB cards offer the opportunity to stream and/or record TV and serve it up to various ‘receivers’ (and I believe Windows Media Center pretty much does this). The problem is that such cards are only available for free to air broadcasts – no commercial satellite or cable (and likely no free to air HD if the BBC/Ofcom give in to Holywood).

Any other thoughts – please comment below?

[1] These days a 3rd generation games console like an XBox 360 or PS/3 can also double as a media player. Even the Wii can join the party if you hack it a little (with official support often rumoured but never released).

Update 1 Jul 2010 – and a few days after writing this along comes HDBaseT (thanks to The Register for flagging this up). No mention of multi room capabilities, but it looks like exactly the right enabling technology (and could probably be somehow combined with the StarTech stuff that Patrick mentions in comments below).

Update 7 Jul 2010 – the BBC has an article out saying that ‘Analogue TVs no longer sold by UK retailers‘. It lacks detail – how many of those TVs sold in May were capable of receiving an analogue signal (most I’d bet)? The trend was however already clear.



2 Responses to “Video distribution at home”

  1. 1 Patrick O'Dwyer

    StarTech do a range of HDMI distribution amplifiers that support HDCP. I don’t have first hand experience of these devices and they are certainly not the whole answer to digital video distribution, but its a start if you can live with a 50 feet cable limit.

    • 2 Chris Swan

      Thanks Patrick – one of those products that I thought ought to exist but wouldn’t, and it’s nice to be proven wrong. Now I’m left wondering if the HDCP is terminated in the distribution box, or fanned out to each of the endpoints?


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